You're building a SaaS product or internal platform that serves multiple customers, business units, or teams. Right now, you have a single database, a shared schema, and a WHERE clause filtering on tenant_id. It works. The question is: will it still work when you need to move a high-value customer to dedicated infrastructure, when compliance requires physical separation, or when one tenant's query load starts degrading performance for everyone else? Tenant isolation is not just a security concern. It's an architectural decision that shapes your data model, your query patterns, your deployment topology, and your operational flexibility. Make the wrong choice early, and you'll face expensive migrations under pressure. Make the right choice, and you preserve options without over-engineering. Isolation Models and Their Tradeoffs There are three common isolation models: shared schema with row-level filtering, schema-per-tenant, and database-per-tenant. Each has a diff...
You have a monolithic .NET service handling customer orders, inventory checks, and email notifications. A colleague suggests splitting it into three microservices. Another argues the split will triple operational overhead without delivering business value. Both are probably right, but neither answer helps you decide what to do Monday morning. After modernizing multiple legacy .NET systems and operating microservices architectures on both AWS and Azure, I've learned that the decision to split a service is less about embracing distributed systems and more about matching architectural boundaries to the operational consequences your team can actually handle. The wrong split creates alert fatigue, deployment dependencies, and debugging sessions that span five repositories. The right boundary reduces coupling, enables independent deployments, and makes production incidents easier to isolate. Start With the Deployment Boundary, Not the Domain Model The first question is not whether...